“Electrochromism”, a phenomenon wherein the color of a compound changes reversibly with the application of a voltage, has been applied to modulated light window and display devices. In a prior art electrochromic device, an electrochromic layer and electrolyte layer are sandwiched between a pair of electrodes in which at least one is a transparent electrode, and electrochromism is manifested by applying a voltage between these electrodes. This structure is described in JP-A No. 287173/2002.
In JP-A No. 50406/2003, an electrochromic glass plate is described wherein an electrochromic layer, an electrolyte film and an ion storage layer are sandwiched between a pair of transparent conductor (electrode) layers. In this invention, indium-tin oxide (ITO) and fluorine-doped tin oxide (FTO) are used as the transparent electrodes or transparent conductors. A display device using the principle of electrochromism is described in JP-A No. 82360/2002.
The prior art electrochromic device wherein an electrochromic layer and electrolyte layer are sandwiched between a pair of transparent electrodes is well-known. The Inventor has reported an in-plane switching electrochromic device wherein an electrochromic layer and an electrolyte layer are laminated on a substrate carrying two electrodes, as described in Polymer Preprints 2005, 46 (1), 523. Two kinds of in-plane switching electrochromic devices with different lamination sequences which can both perform repeat operation are known. In Chemistry of Materials 1998, 10, p. 2101, the structure shown in FIG. 31, wherein electrochromic layers 1011, 1017 are formed on both sides of an electrolyte layer 1012, and sandwiched between a pair of electrodes 1013, 1014 connected to a power supply 1015 as shown in FIG. 31, is reported.
[Patent document 1] JP-A No. 287173/2002
[Patent document 2] JP-A No. 50406/2003
[Patent document 3] JP-A No. 82360/2002
[Nonpatent document 1] Polymer Preprints 2005, 46(1), 523
[Nonpatent document 2] Chemistry of Materials 1998, 10, p. 2101